This invention relates to a clutch typically used in coupling an engine and transmission, and more particularly, the invention relates to a multiple disc clutch.
Clutches typically include a clutch cover secured to a flywheel. A pressure plate is arranged between the clutch cover and the flywheel and forces a friction disc, which is arranged between the pressure plate and flywheel, into engagement with the flywheel to couple the engine and transmission together. Typically, a resilient member such as clutch straps interconnect the pressure plate and clutch cover together for rotation with one another. The clutch straps permit movement along the axis of rotation of the clutch to permit movement of the pressure plate relative to the clutch cover. The clutch straps retract the pressure plate away from the flywheel upon actuation of a clutch pedal, which creates a condition that permits self-disengagement of the friction disc from the plate and flywheel.
Multiple disc clutches include an intermediate plate arranged between the pressure plate and the flywheel. A friction disc is arranged between the pressure plate and the intermediate plate and another friction disc is arranged between the intermediate plate and the flywheel. Of course, additional pressure plates and friction discs may be used. As with single disc clutches, the clutch straps or other such device retracts the pressure plate from the flywheel to disengage the clutch. The friction discs and the intermediate plate are expected to self-disengage once the pressure plate has been retracted. However, due to the number of components, weight of the components, frictional forces between the components, and other factors, the intermediate plate and friction disc may not fully disengage from the plates and flywheel. As a result, the friction discs and intermediate plate may vibrate causing noise or drag against the flywheel resulting in parasitic losses. Therefore, what is needed is a multiple disc clutch assembly that permits self-disengagement of the friction discs to reduce and/or eliminate vibrations and parasitic losses.